Update Contact List Contacts

Update the contact list contacts in an organization by applying the given action over contacts. Before applying it, the contacts
are created or updated in case they already exists, and are opt in to all organization channels by default in case action is add or overwrite.
By providing the opt_in_to field you can choose to only opt in the contacts to specific channels. The contact list must be active.

The following actions are supported:

• add: Adds the contacts to the contact list.

• remove: Removes the contacts from the contact list.

• overwrite: Removes all contacts from the contact list and adds the given contacts to it.